This invention relates to a nail end plate and more particularly to a nail end plate for use with wooden ties.
Many types of connector plates have been previously described for fastening a pair of adjacent wooden members such as structural members in a roof truss or the like. The conventional connector plates are designed to be secured or penetrate into the longitudinal grain of the structural members.
Wooden ties such as cross ties are normally cut from green wood and are allowed to dry or cure prior to being used. The wooden ties frequently develop splits or cracks in the ends thereof which renders the cross tie unusable unless some means is provided to close the splits. Applicant has previously devised end plating machines for wooden ties which employ hydraulically operated platens which compress the ends of the tie to close the cracks therein. Nail plates are then driven into the ends of the compressed tie. When the pressing or squeezing pressure is released from the tie, the nail plates tend to maintain the ends of the tie in the closed position. In other words, the splits are prevented from reopening through the use of the nail plates. However, the nail plates previously available have been those types of plates used in the fabrication of roof trusses or the like. The nail plates of the prior art sometimes "work" out from the ends of the tie which cause the splits to reopen. Further, some of the conventional connector plates have been found to tear or split themselves.
U.S. Pat. No. 3,241,424 to Moehlenpah et al. discloses a prior art nail plate designed for use as a connector plate for trusses as opposed to a nail end plate for wooden ties. Applicant's invention will not perform as a truss connector plate and is not engineered or designed to function as a truss connector plate. Applicant's nail end plate as disclosed herein is designed for split control retention in hard wood cross ties and cannot be forced or pressed into soft structural wood members. Applicant's nail end plate will not drive into structural lumber and will physically collapse before fully penetrating the structural lumber.
Applicant's nail end plate differs from that of Moehlenpah and other types of truss connector plates since applicant's invention pertains to split control nail plates for application to wood cross ties that are driven into the end grain fibers of the cross tie. Truss connector and fastener plates such as that of Moehlenpah are engineered and invented for their intended use of fastening two structural lumber members connected together to present the longitudinal strength needed for such structural members used as trusses in the construction industry that must meet certain Truss Plate Institute specifications.
Applicant's invention as described herein represents many improvements over the prior art including the Moehlenpah '424 connector plate. When comparing the overall holding action of applicant's invention to the Moehlenpah '424 connector plate, it is readily apparent that it is impossible for the Moehlenpah plate to have smooth perimeters or edges. If the Moehlenpah plate is cut at various locations, a smooth perimeter would not be obtained. Applicant's invention is engineered and designed to provide a smooth, continuous perimeter for safety purposes. As used herein, a smooth, continuous perimeter or edge is defined as being without interruptions and without having any sharp corners. The perimeter of the Moehlenpah '424 connector plate is not smooth and continuous since it does have openings extending thereinto which create sharp edges thereby creating safety hazards. A further advantage to applicant's invention when considering the prior art such as the Moehlenpah '424 connector plate is that applicant's plate can be cut between rows of openings thereby making the plate narrower while still maintaining a smooth, continuous perimeter without any interruptions therein whatsoever.
Further, applicant's nail end plate results in a plate which leaves no open webs as in the prior art devices. The open webs in the prior art devices reduce their strength and holding power. Applicant's invention with the smooth perimeter and rounded corners presents a complete outer perimeter of strength which alone is deemed to be an improvement over the prior art patents in that additional strength is gained within a specified area. Applicant's invention also provides new and improved technology over the prior art since the design thereof results in a twin staple rotary action, action and reaction. Unlike prior art patents where the strength of one tooth is transmitted to the adjacent tooth for holding power, the twin tooth staple action of applicant's invention transmits holding power horizontally and angularly to every sixth tooth, thus providing a more even holding force and causing the twin staples to produce a rotary force of the invented tooth which reacts as a wedging effect of a twin staple trying to rotate about its force line axis, thus gripping and holding a constant tension of the teeth to the wood. The greater the opposing forces try to reopen the closed split in the cross tie, the more force is applied to the upper and lower twin staple, thus gripping the end grain tighter.
Numerous tests have been performed which demonstrate the superior holding and gripping power of applicant's invention for wood end grain use versus truss plates of the prior art. The plates of the prior art such as that in the Moehlenpah '424 patent tend to back out of the tie after the squeeze pressure has been released since they have no engineering qualities to maintain their position in end grain application. In fact, the tooth design of the Moehlenpah '424 device is detrimental because the shank root is larger than the shank portion of the tooth, thus creating a web-shape resistance before the plate is completely sealed flat against a tie end. This in itself is not suitable for end grain application as the web-shape tends to force the plate back out of the tie.
When squeezing pressure is removed from the tie and the tie is inserted beneath railroad track rails, the trains, which sometimes have flat spots on their wheels, produce a tremendous vibration that is transmitted to the railroad tie. A poorly designed plate will come loose and/or back out and release the split, which in some cases will cause the spikes securing the rail to the tie to loosen and thereby create a safety hazard.
Therefore, it is a principal object of the invention to provide an improved nail end plate for wooden ties.
A further object of the invention is to provide a nail end plate for wooden ties including teeth which are formed so as to positively maintain the end plate on the wooden tie.
A further object of the invention is to provide a nail end plate which has a plurality of teeth extending therefrom, with the teeth forming pairs of staples to positively maintain the end plate in the tie.
A further object of the invention is to provide a nail end plate having a design so that the load value is transmitted from pairs of teeth to adjacent pairs of teeth to aid in preventing the plate from failing.
A further object of the invention is to provide a nail end plate having a smooth, continuous perimeter with rounded corners which is uninterrupted by any openings extending thereinto thereby eliminating safety hazards.
Still another object of the invention is to provide a nail end plate having a design such that a plate may be cut to create a narrower end plate while still maintaining the smooth, continuous and uninterrupted perimeter thereof.
Yet another object of the invention is to provide a nail end plate which achieves twin staple rotary action, action and reaction.
These and other objects will be apparent to those skilled in the art.